The invention relates to an impeller for a delivery pump which constructed as a side channel pump, provided is in particular for delivering fuel in a fuel container, and which, at its ends, in each case has a ring of guide vanes bounding vane chambers spaced apart from its radially outer rim and is provided to be arranged between housing parts of the delivery pumps.
Delivery pumps for delivering fuel from fuel containers are frequently designed as side channel pumps and known from practical use. The delivery of the fuel is carried out from an inlet channel via the rings of the vane chambers and in partially annular channels arranged in the housing parts to an outlet channel. In the rings of vane chambers arranged at both ends of the impeller, a higher pressure is produced on one end than on the other end during the delivery of the fuel. This pressure difference is particularly high, especially in axial-flow side channel pumps in which the vane chambers are connected to one another.
The disadvantage with the known delivery pump is that, as a result of the pressure difference at the ends of the impeller, flow losses arise as a result of bypass flow around the outer rim of the impeller. These flow losses lead to a reduction in the efficiency of the delivery pump. Furthermore, as a result of the bypass flow, dirt particles contained in the fuel are introduced between the impeller and the housing parts. As a result, the impeller wears, in particular at its rim, which leads to a rise in the flow losses.
Consideration could be given to providing the impeller with a particularly wear-resistant layer or to keeping the tolerances between the housing parts and the impeller particularly small. However, this leads to a high fabrication outlay for the impeller.
The invention is based on the problem of configuring an impeller of the type mentioned at the beginning in such a way that flow losses and wear at the rim of the impeller are kept particularly low.